Original Sin, Crucible, Sheffield; <br></br>Johan Padan, Riverside Studios, London; <br></br>Nebuchadnezzar, Latchmere, London

A sexual magnet without much pulling power

'What would happen if you put life on the stage?", the pretty-boy hero of Original Sin asks his playwright pal. "Would that frighten them?" Putting life on the stage is what Peter Gill, whose work is being commemorated in the Sheffield Crucible's current season, is about. His most recent play, The York Realist, did so exquisitely. His latest, a queer refit of Wedekind's Lulu, is rather less successful. Set in 1890s London and Paris, it traces the sexually magnetic Angel's rise and fall from street-kid to aristocrats' plaything to Whitechapel whore. But Angel's several-year journey sometimes seems to be taking place in real time, as Gill struggles over three-and-a-half hours to dramatise the degrading power of erotic obsession.

In a production, by Gill himself, that lacks urgency (its scene changes are defiantly unhurried), the writer's interest lies in the capacity of love to enslave. A succession of Victorian gents are ruined by their subjection to Angel's charms. But the play is about two kinds of privilege, beauty and money, and Angel too is ruined, as much by his lack of one as by his abundance of the other. Designer Alison Chitty recreates fin de siècle London with meticulous elegance, and Gill's recreation of that world is initially appealing.

But all this ruination ultimately makes for rather dingy theatre. Gill opts for a heightened period idiom that accommodates several lovely turns of phrase, and several more clunkingly bathetic ones as the toffs decry their lot. His characters' self-absorption is alienating and (deliberately?) ridiculous. Their defining characteristic, their inability to act positively, is not the stuff of dynamic drama. This viewer found himself urging Angel's lovers – "Destroy me! Finish me!", sobs one, kneeling at Angel's feet – to get a life.

The problem is partly that Andrew Scott's Angel is such a prat. Gill's point may be that sexual obsession operates independently of its object's character. Fair enough – but I'd rather not have to spend so long in the company of such a pompous, petulant little narcissist to have the point proven. When his admirer Arthur coos at him, "How amazing you are! How original you are!", it's all too easy to disagree. Scott is a confident presence at the hub of Gill's drama, but can't make us feel for Angel, can't expose the heart beating inside the hard shell.

Elsewhere, there are flickers of theatrical life. John Normington varies the rhythm of a downbeat evening as Angel's lively, destitute guardian Slavin – the play's amiable narrator. There are some entertaining interruptions to the drawing room woe, as when several Keystone Cop-style gendarmes chase Angel across Paris. Gill and the cast have fun caricaturing some of the lesser parts. But for a play about erotic desire, Original Sin generates very little heat.

Dario Fo, the Nobel Prize-winning provocateur of Italian theatre, has a new solo show – Johan Padan – about one of Christopher Columbus's lackeys who gets caught up in the Spanish Conquest of the new world. It's performed by Mario Pirovano, a buck-toothed Iain Duncan Smith lookalike and long-term Fo sidekick.

Pirovano is a hugely likeable narrator, who bookends the monologue by blithely chatting to the audience. He animates with great physical expressiveness Fo's bawdy, simplistic tale of an Italian runaway who wins the hearts of America's threatened natives. Placing a clown in history allows Fo to expose with humour some of colonialism's most flagrant hypocrisies: its religious double standards, its condemnation of tribal brutality. But the play isn't as dissident as it thinks: it still looks at the Conquest from the European perspective, and persists in treating its non-individualised Indians as noble savages. And it seems overlong, perhaps because several of Fo's comic darts miss their target when delivered in Pirovano's confident but imprecise English.

Fo would approve of young writers taking potshots at corporate culture. Glyn Cannon does so with Nebuchadnezzar, a black comedy based, apparently, on the travails of the ancient Babylonian king. We're in the cool office complex of a pharmaceutical giant. High-flier Dryden is getting above himself, and CEO Jerome is forced to engineer his comeuppance. James Reid's production starts with a swagger, spoofing management gobbledegook and the homogeneity of office life as three mannequin secretaries strut robotically across the stage. When his seminar presentation is sabotaged, John Fairfoul's Dryden collapses into growling bestiality. Only Tess Mawle's Eliza is left, the last human standing in the big business jungle. The latter is the only character with whom we're invited to identify, in a crude satire that soon, regrettably, starts taking itself seriously. While few would argue that corporate power is ruthless, it's personified here, by Johnnie Lyne-Pirkis's Jerome, as some kind of irresistible demonic force.

Cannon's Manichaean point, that big business stifles the creativity of its employees, isn't convincing. Doesn't business thrive by exploiting that creativity? Nevertheless, Cannon's self-assurance is refreshing, and suggests he may yet match with accomplishment his ambition to nail the violence of capitalism.

Kate Bassett returns next week

'Original Sin': Crucible, Sheffield (0114 249 6000), to 22 June ; 'Nebuchadnezzar': Latchmere, London SW11 (020 7978 7040), to 29 June